January 30, 1917 – Despite all that can be said to the contrary – the power and resources of the United States are very great.

Johann Heinrich von Bernstorff, the German ambassador to Washington, had warned Berlin against provoking the Americans. But on January 30 Germany announces unrestricted submarine warfare in the eastern Atlantic, targeting any ships heading to an Allied port. This photo shows Model T’s coming off the production line at a Ford plant in Philadelphia in 1917.